Show file name and size on images on hover

res/css/views/elements/_ImageView.scss

@@ -79,6 +79,11 @@ $button-gap: 24px;
     font-weight: bold;
 }
 
+.mx_ImageView_title {
+    color: $lightbox-fg-color;
+    font-size: $font-12px;
+}
+
 .mx_ImageView_toolbar {
     padding-right: 16px;
     pointer-events: initial;

res/css/views/messages/_MImageBody.scss

@@ -17,6 +17,28 @@ limitations under the License.
 
 $timeline-image-border-radius: 8px;
 
+.mx_MImageBody_banner {
+    position: absolute;
+    bottom: 4px;
+    left: 4px;
+    padding: 4px;
+    border-radius: $timeline-image-border-radius;
+    font-size: $font-15px;
+
+    pointer-events: none; // let the cursor go through to the media underneath
+
+    // Trying to match the width of the image is surprisingly difficult, so arbitrarily break it off early.
+    max-width: min(100%, 350px);
+
+    text-overflow: ellipsis;
+    white-space: nowrap;
+    overflow: hidden;
+
+    // Hardcoded colours because it's the same on all themes
+    background-color: rgba(0, 0, 0, 0.6);
+    color: #ffffff;
+}
+
 .mx_MImageBody_placeholder {
     // Position the placeholder on top of the thumbnail, so that the reveal animation can work
     position: absolute;

src/components/views/elements/ImageView.tsx

@@ -38,6 +38,7 @@ import UIStore from '../../../stores/UIStore';
 import { ViewRoomPayload } from "../../../dispatcher/payloads/ViewRoomPayload";
 import { KeyBindingAction } from "../../../accessibility/KeyboardShortcuts";
 import { getKeyBindingsManager } from "../../../KeyBindingsManager";
+import { presentableTextForFile } from "../../../utils/FileUtils";
 
 // Max scale to keep gaps around the image
 const MAX_SCALE = 0.95;
@@ -546,6 +547,9 @@ export default class ImageView extends React.Component<IProps, IState> {
             >
                 <div className="mx_ImageView_panel">
                     { info }
+                    <div className="mx_ImageView_title">
+                        { presentableTextForFile(this.props.mxEvent.getContent(), _t("Image"), true) }
+                    </div>
                     <div className="mx_ImageView_toolbar">
                         { zoomOutButton }
                         { zoomInButton }

src/components/views/messages/MFileBody.tsx

@@ -344,7 +344,7 @@ export default class MFileBody extends React.Component<IProps, IState> {
                         </a>
                         { this.context.timelineRenderingType === TimelineRenderingType.File && (
                             <div className="mx_MImageBody_size">
-                                { this.content.info && this.content.info.size ? filesize(this.content.info.size) : "" }
+                                { this.content.info?.size ? filesize(this.content.info.size) : "" }
                             </div>
                         ) }
                     </div> }

src/components/views/messages/MImageBody.tsx

@@ -37,6 +37,7 @@ import { ImageSize, suggestedSize as suggestedImageSize } from "../../../setting
 import { MatrixClientPeg } from '../../../MatrixClientPeg';
 import RoomContext, { TimelineRenderingType } from "../../../contexts/RoomContext";
 import { blobIsAnimated, mayBeAnimated } from '../../../utils/Image';
+import { presentableTextForFile } from "../../../utils/FileUtils";
 
 enum Placeholder {
     NoImage,
@@ -446,6 +447,21 @@ export default class MImageBody extends React.Component<IBodyProps, IState> {
             gifLabel = <p className="mx_MImageBody_gifLabel">GIF</p>;
         }
 
+        let banner: JSX.Element;
+        const isTimeline = [
+            TimelineRenderingType.Room,
+            TimelineRenderingType.Search,
+            TimelineRenderingType.Thread,
+            TimelineRenderingType.Notification,
+        ].includes(this.context.timelineRenderingType);
+        if (this.state.showImage && this.state.hover && isTimeline) {
+            banner = (
+                <span className="mx_MImageBody_banner">
+                    { presentableTextForFile(content, _t("Image"), true, true) }
+                </span>
+            );
+        }
+
         const classes = classNames({
             'mx_MImageBody_placeholder': true,
             'mx_MImageBody_placeholder--blurhash': this.props.mxEvent.getContent().info?.[BLURHASH_FIELD],
@@ -473,6 +489,7 @@ export default class MImageBody extends React.Component<IBodyProps, IState> {
                 <div style={sizing}>
                     { img }
                     { gifLabel }
+                    { banner }
                 </div>
 
                 { /* HACK: This div fills out space while the image loads, to prevent scroll jumps */ }

src/i18n/strings/en_EN.json

@@ -2134,9 +2134,9 @@
     "Error decrypting attachment": "Error decrypting attachment",
     "Decrypt %(text)s": "Decrypt %(text)s",
     "Invalid file%(extra)s": "Invalid file%(extra)s",
+    "Image": "Image",
     "Error decrypting image": "Error decrypting image",
     "Show image": "Show image",
-    "Image": "Image",
     "Join the conference at the top of this room": "Join the conference at the top of this room",
     "Join the conference from the room information card on the right": "Join the conference from the room information card on the right",
     "Video conference ended by %(senderName)s": "Video conference ended by %(senderName)s",

src/utils/FileUtils.ts

@@ -37,7 +37,7 @@ export function presentableTextForFile(
     shortened = false,
 ): string {
     let text = fallbackText;
-    if (content.body && content.body.length > 0) {
+    if (content.body?.length > 0) {
         // The content body should be the name of the file including a
         // file extension.
         text = content.body;
@@ -58,7 +58,7 @@ export function presentableTextForFile(
         text = `${fileName}...${extension}`;
     }
 
-    if (content.info && content.info.size && withSize) {
+    if (content.info?.size && withSize) {
         // If we know the size of the file then add it as human readable
         // string to the end of the link text so that the user knows how
         // big a file they are downloading.